1. Field
Exemplary embodiments of the inventive concept relate to an air exhaust apparatus installed at a ceiling, wall or floor which is an end of a duct of centralized exhaust system. More particularly, exemplary embodiments of the inventive concept relate to an air exhaust apparatus capable of improving capture and exhaust performance. Exhaust airflow in the duct caused by a central exhaust blower may revolve a propeller which is connected to a shaft and a vortex impeller. Thus, the vortex impeller may revolve to make a vortex under the air exhaust apparatus. The air exhaust apparatus may efficiently capture and exhaust sources of air pollution due to the vortex.
2. Description of the Related Art
Generally, large structures such as an office building, a shopping mall, a manufacturing facility has an outdoor air supply blower and an air exhaust, and has an indoor duct for an indoor air ventilation. An air diffuser having a louver may be installed at a ceiling, wall or floor which is an end of the duct. The air diffuser is a device to provide clean air, and there are varieties of technologies and designs patents as described in FIG. 1. For example, U.S. Pat. No. D325,434 entitled “Air Diffuser”, U.S. Pat. No. D521,631 entitled “Air Diffuser”, U.S. Pat. No. 3,403,614 entitled “Environmental Enclosure With Ceiling Air Plenum”, U.S. Pat. No. 3,559,560 entitled “Ceiling Boxes For Distributing Air”, U.S. Pat. No. 4,020,752 entitled “Air Diffuser with Modular Core”, U.S. Pat. No. 5,807,171 entitled “Air Diffuser Apparatus”, U.S. Pat. No. 6,135,878 entitled “Modular Core Air Diffuser”, U.S. Pat. No. 6,935,571 entitled “Air Diffuser”, and U.S. Pat. No. 7,645,188 entitled “Air Diffuser Apparatus”.
However, the air diffuser having a louver to distribute clean air evenly into indoor may also be used as an exhaust outlet for exhausting, the exhaust outlet may decrease inhale air flow velocity for collecting the sources of pollution, so that capture efficiency may be worse.
In addition, ventilation of a traditional exhaust outlet may be dependent on air flow. Polluted air from indoor may flow out and clean air from outside may flow in for the ventilation to decrease the concentration of indoor air pollution. Thus, ventilation rates or air change rates may be determined according to indoor condition, then supply and exhaust air flow may be calculated to fit the ventilation.
However, the excessive ventilation rate which is needed to clean may cause energy waste issue, because the sources of pollution which is far from the exhaust outlet or air diffuser may be hard to be carried out. This is simply not the only electrical cost of operating a ventilation system, resulting in the waste of energy due to excessively discharging room air containing heating and cooling energy.
Main cause of these problems is that a certain degree of capture velocity is needed to carry the sources of pollution with exhaust air.
Capture velocity is defined as an air velocity at any point in front of the exhaust outlet necessary to overcome opposing air currents and to capture the contaminant at that point causing it to flow into the exhaust.
However, the capture velocity is rapidly decreased in inversely proportional to square of the distance far from the exhaust outlet. Generally, the capture velocity may be lower than 10% of exhaust face velocity (flow rate at surface of the exhaust outlet) where is far from the exhaust outlet by a diameter of the exhaust outlet.
Because of these reasons, a traditional ventilation system has a problem with low capture efficiency and wasting of energy.